Field of the Invention
The present invention relates to a ventilation system for a tunnel section or a covered road.
Description of the Related Art
Increasing traffic congestion is constantly putting more pressure on the environment from polluting substances released from vehicles.
Vehicles, because of their use of fossil fuels, produce pollutants such as nitrogen oxides and also soot particles. In addition, traffic also produces particulates from products released through wear of the brakes and tyres of vehicles.
There are statutory regulations which provide standards for the maximum permitted exposure of the environment to the abovementioned pollutants caused by traffic, so that environmental pollution can be limited to some extent.
The release of pollutants is at its peak particularly during rush hours (peak loads of the section) when a very large number of vehicles are using the road.
A problem can occur at the mouths of tunnels and covered road sections, where the pollutants can accumulate inside the tunnel because of the reduced discharge to the environment, and such pollutants can be present in high concentrations at the mouths. There are ventilation systems which create a constant air flow in the tunnel in order to freshen the air and discharge the pollutants present in the tunnel to the environment at the entrance and/or exit or at an air outlet point.
An outflow of polluted air can then occur at the entrances and exits of the tunnel or at the air outlet point, so that the abovementioned standards can be seriously exceeded, in particular during peak loads of the tunnel.